As seemingly damning as the headlines may be, the results of the study don't prove that harassment directly causes young gay people to become suicidal or hurt themselves. Still, the research is the first to show what happens over time to teens who are bullied and victimized, said study co-author Brian Mustanski, an associate professor at Northwestern University's Department of Medical Social Sciences.

It may seem obvious that bullying and a lack of support from loved ones would make people more suicidal. But "sometimes the things that we think are important still have to get confirmed with science," Mustanski said.

"It's surprising how negative those effects are," he added. "Victimization turned out to be really important. It was far and away the most important risk factor."

Previous research has suggested that gay, lesbian, bisexual and transgender (LGBT) children are more likely to be suicidal and hurt themselves. A study released in the journal Developmental Psychology last year found that these people who were bullied as children were about 2.5 times more likely as others to be clinically depressed as young adults.

In the new study, reported in the current issue of the American Journal of Preventive Medicine, researchers surveyed 246 LGBT youth aged 16 to 20 and followed them over several years to see what happened to them. Fifty-seven percent of the participants were black; about half were female.

Being bullied (over the time period of the study) and a low level of support from others boosted the risk that the teens would become suicidal. Bullying also boosted the risk that they would try to harm themselves. Over the 2.5-year study, slightly more than 15 percent of the people in the survey reported trying to harm themselves.

On average, 8 percent of the participants reported hurting themselves in the prior six months, Mustanski said. Seven percent of those who didn't report being victimized said they'd harmed themselves, compared to 11 percent of those who'd reported being victimized. Overall, a history of being bullied more than doubled the odds for self-harm, the researchers found.

However, those who had social support -- "support from family and peers, meaning that the young person would say they have someone to go to when they have a tough time, someone is looking out for them" -- were less likely to be suicidal, Mustanski added.

N. Eugene Walls, an assistant professor of social work at the University of Denver, said the study confirms other findings about the effects of anti-gay bullying.

"As more and more research accumulates, those who wish to ignore anti-gay bullying or dismiss it as normal adolescent behavior and teasing are going to have an increasingly difficult argument to make that bullying is not that serious," he said.

What should parents do?

"Research indicates that they are unlikely to be able to change their child's sexual orientation. So even though it may be difficult, sexual orientation is likely to be something about their child that will require acceptance," said Jennifer Langhinrichsen-Rohling, a professor of psychology at the University of South Alabama.

Mustanski said young people themselves can find support through gay-straight alliances on campuses, youth programs at local gay community centers and online sites.

He recommended the American Foundation for Suicide Prevention's list of warning signs of suicide.